Broach.



J. OAKLEY.

BBOACH.

A'PPLIGATIOH mum JAN. 29, m4.

1,121,126, Patented Dec. 15,1914.

WITNESSES: I INVENTOR. f6. QM 2:

ATTORNEYIS.

Ht. NONRIS PETERS CO4, PHOT'O-LITHO.. WASH 'NG YUN,.D.

. UNITED sTAT s *P'Arnnr OFFICE.

JOHN OAKLEY, or srnfnorinrn, MASSACHUSETTS.

Specification of Letters latent.

snoacn.

Patented Dec. 15, 1914 Application filed January 29, NHL-Serial No. 815,179.

To all whom it may concern:

Be it known that 1,.Jonn OAKLEY, a subject of the King of Great Britain, residing at Springfield, 1n the county of l-lampden and State of Massachusetts, have invented a new and useful Breach, of which the following is a specification.

My invention relates to improvements in tools known as drifts or breaches, which are employed to cut grooves or keyways in the )OlCS of gears, pulleys, or any article of a a re or less similar nature, and consists of 2. body part which is round in cross-section and has a longitudinal chip passage therein which opens through one side thereof, and a row of teeth or cutters on said body -part, the latter having also therein, between or in front of said cutters, clearance holes or openings for chips, said openings extending from the outside of saidbody part to said passage, and being usually arranged at an incline, from their outer ends to their inner ends, which is away from the direction of the tool in operation, all as hereinafter set forth. Usually in this broach eachcutter in the row is set a trifle higher than the preceding one in the row, in the direction of movement of the broach in operation. The objects of my invention are, first, to produce a tool, of the class described above that is self-clearing, hence will do work 0 a superior character, because the chips as hey are out immediately ass away from e cutting field andso 0 not interfere th the broaching oaeration or damage in any way the sides of t 1e slots or holes which are produced by such operation; second, to provide such a tool with lateral openings that not only serve to take care of the chips the instant they are made, but also permit the pro er rake to be given to the cutters, such raiie being varied to meet the conditions incident to dill'erent materials upon which the tool is used, and, third, to produce a shorter and more durable broach than has heretofore generally been required for the same class of work, and a broach that is, withal, highly practicable and cilicient.

Other objects will appear in the course of the following description.

I attain the objects and secure the advantages of my invention by the means v illustratedin the accompanying drawings,

in which Figure 1 is alongitudinal sectional view of a breachv that embodies a practical form .0 my invention and, Fig. 2, a cross-sectio: through such broach, taken on ulines 2-& looking v inthe direction of: the associate arrow, in Fig. 1.

Like numerals designate like part throughout the several views.

Since a broach of this type may be prc vided with a threaded shank to screw int a threaded chuck, or with a part to be er gaged by a jaw chuck, or may be drive from the rear end, the front or leadingen portion of my broach is omitted,;it bein understood that such leading terminal por tion may be made ofany length and shap desired. No part of my inventionis ir volved in the aforesaid leading terminz portion.

My broachcomprises a body 1, which 5 round in cross-section, and a-iseries or ro" of teeth or cutters 3fthat are usually forme integraIwith such body, saidbody havin therein a lateral clearance openin or pa: sage 4 in advance of each of said cutter and a longitudinal passage 5, with whic said passages 4: communicate at their inne ends. The passage 5 is the main clearan passage, and usually opens through the re: end of the body 1.

In order to produce the quickest as we as the best results, the cutting edge, whic is the highest part or the part most remo from the axis of the body 1, of each cutter is a very little higher or sli htly more r mote from such axis than is the corresponr ing edge of the next cutter in front, tl foremost cutter having the lowest cuttir edge and the rearmost cutter having tl highest cutting edge. More or less depa ture from this arrangement may, howeve be made, as must be apparent to one skilh in the art. The lateral passages 4 are front of their respective cutters 3. The ch or cutting made by any cutter 3 is usual as wide as the cutter, and in some cases m: spread so as to be even wider, wherefo each passa e 4 should at least be as wide the cutter behind it, in order to accomm date such chip or cutting. Each passage is. pitched or inclined inwardly or rea wardly. The inward and rearward pitch each passage 4 serves two purposes, first, channel that is best adapted to guide t cuttings into the passage 5 is thus provide and, second, provision is made whereby t desired rake can without difficulty be giv to the cutterbehind such passage l, the rake in question-being indicatedat 6. This matter of obtaining the proper rake is very important, because much of the success of the operation of a tool of this kind depends thereon, consequently the location of clearance passages in front of the cutters, whereby the rear walls of such passages coincide with or are continuations of the pitched front ends of said cutters, is of great value. The passage 5 is located in one side of the body 1, and each passage 4 extends inwardly far enough to open into or connect with said passage 5 through the interior longitudinal wall of the same.

In practice the left-hand or forward part of the body 1 is introduced into or passed through a round hole in the gear, nilley, or other article to be broached, wliic h hole is of the same diameter as that of said body, and the tool is drawn or driven through such hole, sullicient l'orce being applied to accomplish this operation. The cutters 3, as they are thus forced through the aforesaid hole, cut away the metal and form the groove or opening which the breach is designed to produce. The metal removed in this manner by each cutter 3 at once enters the passage l in front of the cutter, whereb\' the path of each succeeding cutter is kept clear. The cutting in question continues through the passage l into the passage 5 into which said passage 4: opens, and may escape from said passage 6 through the bottom of the rear end thereof. By reason of the fact that the passage 5 opens through one side of the body 1, the tool clears itself with the least possible amount of dilliculty, the chips or cuttings passing directly through the passages a and 5 either into the original opening through the article being broached, from whence they easily and quickly escape by way of the open end of said passage 5, or out of the bottom of said passage 5, according to the position of said last-mentioned passage relative to said article.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is-

.*\s an improved article of manufacture, a breach comprising a body provided with, cutters, and having a longitudinal passageii and lateral passages therein said longitu dinal passage opening through one side of the same, and being common to said lateral passages, and each of the latter opening in front of one of said cutters.

JOHN OAKLEY.

\Vitnesses F. A. Curran, t-. lfianmaa'ns.

65:95:: a! this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). C. 

